I want to put large format tiles in a 10 x 10' bathroom over ditra. I have a solid flooring substrate but it is sloped, losing 1 3/8" over 8 feet. I am concerned about the weight of this much SLC (and the cost). Can I reduce the thickness needed by adding sheets of ply in the low area and then use SLC over the different thicknesses of plywood?
Concrete – use self-levelling cement over different levels of plywood
plywoodself-leveling-concretetiling
Best Answer
You can add plywood, but I would use deck mud to level those large areas. Since you'll be applying ditra you don't need to feather anything. You're just needing a "fairly level" surface under the ditra and on top of it.
Self-level is brittle and expensive.